Strength and Endurance in Human Skeletal Muscle, Why Electrical

BackgroundElectrical stimulation has been used to train paralyzed muscle. However, papers often cite that rapid fatigability of muscle compared to voluntary effort. Methods and Procedures; The literature is reviewed over the last 25 years examining the normal recruitment order of motor units, the impact of recruitment order, stimulation frequency and asynchronous recruitment on muscle strength and endurance. Results; Recruitment order has little impact on muscle endurance. However, synchronous stimulation (where all units are stimulated together, drastically reduces muscle endurance. Stimulation frequency above 20 Hertz also reduces endurance. Conclusions; Electrical stimulation of muscle in people with paralysis shows poor torque and endurance due to the fact that present electrical stimulators do not mimic the normal recruitment method and frequency of the human body.